Science and Technology I · Textbook solutions

Lenses

Every solved example, exercise, and miscellaneous question, in the order the textbook teaches them. Plus every board question asked from this chapter. · 14 questions

Exercise

14 q

Ex Q1 $Match the columns in the following table and explain them. Column 1 Column 2 Column 3 Farsightedness Nearby object can be seen clearly Bifocal lens Presbyopia Far away object can be seen clearly Concave lens Nearsightedness Problem of old age Convex lens$
Ex Q2 $Draw a figure explaining various terms related to a lens.$
Ex Q3 $At which position will you keep an object in front of a convex lens so as to get a real image of the same size as the object ? Draw a figure.$
Give scientific reasons:
Ex Q4(a) $Simple microscope is used for watch repairs.$
Ex Q4(b) $One can sense colours only in bright light.$
Ex Q4(c) $We can not clearly see an object kept at a distance less than 25 cm from the eye.$
Ex Q5 $Explain the working of an astronomical telescope using refraction of light.$
Distinguish between:
Ex Q6(a) $Farsightedness and Nearsightedness$
Ex Q6(b) $Concave lens and Convex Lens$
Ex Q7 $What is the function of iris and the muscles connected to the lens in human eye?$
Solve the following examples.
Ex Q8(i) $+1.5\ \text{D}$
Ex Q8(ii) $5\ \text{cm}$
Ex Q8(iii) $2$
Ex Q8(iv) $60\ \text{cm}$

Column 1	Column 2	Column 3
Farsightedness	Nearby object can be seen clearly	Bifocal lens
Presbyopia	Far away object can be seen clearly	Concave lens
Nearsightedness	Problem of old age	Convex lens

What the board has asked from this chapter

Questions per paper · 12 papers · 2016 to 2026

June 2026

2 q

Q2(B)(ii) $एका बहिर्गोल भिंगाचे नाभीय अंतर 40 cm आहे, तर त्या भिंगाची शक्ती किती असेल ? The focal length of a convex lens is 40 cm. What is its power?$
Lens Formula and Magnification
Q4(ii) $खालील आकृतीचे निरीक्षण करून विचारलेल्या प्रश्नांची उत्तरे लिहा : (अ) वरील आकृतीत दर्शवलेल्या दृष्टिदोषाचे नाव लिहा. (ब) या दृष्टिदोषाची कारणे लिहा. (क) या दोषाचे निराकरण कसे केले जाते ? (ड) या दृष्टिदोषाचे निराकरण करणारी आकृती काढा. Observe the following figure and answer the questions given below: (a) Name the defect of vision represented in the above figure. (b) State the reasons for this defect. (c) How is it corrected? (d) Draw the diagram to show the correction of this defect.$
Human Eye and Defects of Vision

March 2026

2 q

Q1(A)(v) $निरोगी मानवी डोळ्याचे सुस्पष्ट दृष्टीचे लघुत्तम अंतर ____ आहे. For normal human eye, the minimum distance of distinct vision is ______.$
Tap an option to check your answer.
Human Eye and Defects of Vision
Q4(i) $25$
Image Formation by Lenses

July 2025

3 q

Q1(B)(iii)

योग्य जोडी जुळवा : स्तंभ ‘अ’ स्तंभ ‘ब’ दूरदृष्टिता (अ) दूरच्या वस्तू स्पष्ट दिसतात. (ब) जवळच्या वस्तू स्पष्ट दिसतात. (क) दूरच्या वस्तू स्पष्ट दिसत नाहीत. Match the pair: Group 'A' Group 'B' Farsightedness (a) Faraway object can be seen clearly (b) Nearby object can be seen clearly (c) Faraway object cannot be seen clearly

स्तंभ ‘अ’	स्तंभ ‘ब’
दूरदृष्टिता	(अ) दूरच्या वस्तू स्पष्ट दिसतात.
	(ब) जवळच्या वस्तू स्पष्ट दिसतात.
	(क) दूरच्या वस्तू स्पष्ट दिसत नाहीत.

Group 'A'	Group 'B'
Farsightedness	(a) Faraway object can be seen clearly
	(b) Nearby object can be seen clearly
	(c) Faraway object cannot be seen clearly

Human Eye and Defects of Vision

Q2(A)(ii) $शास्त्रीय कारणे लिहा : डोळ्यापासून 25 cm पेक्षा कमी अंतरावर ठेवलेली वस्तू निरोगी डोळा स्पष्टपणे पाहू शकत नाही. Give scientific reason: We cannot clearly see an object kept at a distance less than 25 cm from the eye.$
Human Eye and Defects of Vision
Q3(vi) $भिंगासाठी वापरले जाणारे कार्टेशिअन चिन्ह संकेत लिहा. Write the Cartesian sign convention for lenses.$
Lens Formula and Magnification

March 2025

2 q

Q1(B)(iv)

योग्य जोडी जुळवा : ‘अ’ स्तंभ ‘ब’ स्तंभ साधा सूक्ष्मदर्शक (a) अतिसूक्ष्म वस्तूंचे निरीक्षण करणे (b) दूरच्या वस्तूंचे निरीक्षण करणे (c) घड्याळ दुरुस्ती करणे Match the columns: Column 'A' Column 'B' Simple microscope (a) used to observe minute objects (b) used to see distant objects (c) used for watch repair

‘अ’ स्तंभ	‘ब’ स्तंभ
साधा सूक्ष्मदर्शक	(a) अतिसूक्ष्म वस्तूंचे निरीक्षण करणे
	(b) दूरच्या वस्तूंचे निरीक्षण करणे
	(c) घड्याळ दुरुस्ती करणे

Column 'A'	Column 'B'
Simple microscope	(a) used to observe minute objects
	(b) used to see distant objects
	(c) used for watch repair

Image Formation by Lenses

Q4(i) $(a) मानवी डोळ्याची शास्त्रीयदृष्ट्या अचूक व नामनिर्देशित आकृती काढा. (b) निरोगी मानवी डोळ्यासाठी सुस्पष्ट दृष्टीचे लघुत्तम अंतर किती आहे ? (c) नाभीय अंतर आवश्यकतेनुसार बदल करण्याच्या नेत्रभिंगाच्या क्षमतेला काय म्हणतात ? (d) कोणत्या दृष्टिदोषांमध्ये वयानुरूप भिंगाची नाभीय अंतर बदलण्याची क्षमता कमी होते ? (a) Draw a neat labelled diagram of human eye. (b) What is the minimum distance of distinct vision for a normal human eye? (c) Name the capacity of the eye lens to change its focal length as per need. (d) Name the defect of eye vision in which the focussing power of eye lens decreases with age.$
Human Eye and Defects of Vision

July 2024

3 q

Q1(B)(iii) $वेगळा घटक ओळखा : निकटदृष्टिता, वृद्धदृष्टिता, दूरदृष्टिता, दृष्टिपटल Find the odd one out: Myopia; Presbyopia; Hypermetropia; Retina$
Human Eye and Defects of Vision
Q2(A)(ii) $शास्त्रीय कारणे लिहा : घड्याळ दुरुस्तीमध्ये साधा सूक्ष्मदर्शी वापरतात. Give scientific reason: A simple microscope is used for watch repairs.$
Simple Microscope
Q3(ii) $खालील किरणाकृतीचे निरीक्षण करून दिलेल्या प्रश्नांची उत्तरे लिहा : (अ) आकृतीमधील उपकरण ओळखा. (ब) दोन भिंगाचा एकत्रित परिणाम काय असतो ? (क) वरील उपकरणाचा उपयोग लिहा. Observe the following ray diagram and answer the questions given below: (a) Identify the instrument shown in the diagram. (b) What is the combined effect of two lenses? (c) Write the use of the above instrument.$
Image Formation by Lenses

March 2024

3 q

Q1(A)(iv) $साध्या सूक्ष्मदर्शीमध्ये ____ भिंगाचा वापर करतात. In simple microscope ______ lens is used.$
Tap an option to check your answer.
Types of Lenses and Terminology
Q2(B)(v) $20\ \mathrm{cm}$
Lens Formula and Magnification

Q3(iv)

\downarrow

मुद्दे $\downarrow$ आकृती $\to$
(a) दोषाचे नाव	____	____
(b) प्रतिमेचे स्थान	____	____
(c) दोषाचे निराकरण करण्यासाठी वापरलेले भिंग	____	____

Points	Figure 1	Figure 2
(a) Name of the defect	?	?
(b) Position of the image	?	?
(c) Lens used to correct the defect	?	?

Human Eye and Defects of Vision

March 2023

5 q

Q1(A)(iii) $The power of a convex lens of focal length 20 cm is ______.$
Tap an option to check your answer.
Lens Formula and Magnification
Observe the figure and answer the following questions:
Q4(i)(a) $Name the defect of vision represented in the above figure.$
Human Eye and Defects of Vision
Q4(i)(b) $State the reasons for this defect.$
Human Eye and Defects of Vision
Q4(i)(c) $How is it corrected?$
Human Eye and Defects of Vision
Q4(i)(d) $Draw the diagram to show the correction of this defect.$
Human Eye and Defects of Vision

March 2022

3 q

Q1(A)(iv) $The power of a convex lens of focal length 25 cm is ________.$
Tap an option to check your answer.
Power of a Lens
Q2(A)(ii) $Give a scientific reason: Simple microscope is used for watch repairs.$
Simple Microscope
Q3(vi) $2F_1$
Image Formation by a Convex Lens

Sr. No.	Position of the object	Position of the image	Nature of the image
1.	Beyond $2F_1$
2.		At infinity
3.			Real, inverted and enlarged

March 2020

2 q

Q1(A)(iii) $For the normal human eye, the near point is at _______ cm.$
Tap an option to check your answer.
Human Eye - Near Point
Q4(i) $Draw a scientifically correct labelled diagram of a human eye and answer the questions based on it: a. Name the type of lens in the human eye. b. Name the screen at which the maximum amount of incident light is refracted. c. State the nature of the image formed of the object on the screen inside the eye.$
Human Eye - Structure and Image Formation

March 2019

5 q

Q1(A)(3) $State whether the given statement is true or false: A concave lens is a converging lens.$
Types of Lenses and Terminology
Q2(5) $F_1$
Image Formation by Lenses
Surabhi from Std. X uses spectacles. The power of the lenses in her spectacles is 0.5 D. Answer the following questions from the given information.
Q3(5)(i) $Identify the type of lenses used in her spectacles.$
Human Eye and Defects of Vision
Q3(5)(ii) $Identify the defect of vision Surabhi is suffering from.$
Human Eye and Defects of Vision
Q3(5)(iii) $Find the focal length of the lenses used in her spectacles.$
Human Eye and Defects of Vision

March 2018

4 q

Q2(4) $Draw a neat and labelled diagram of the structure of the human eye.$
Human Eye and Defects of Vision
Kavita from 10th standard is using spectacles. The power of the lenses in her spectacles is $-2.5$ dioptre.
Q3(5)(a) $Which lenses are used in her spectacles?$
Human Eye and Defects of Vision
Q3(5)(b) $State the defect of vision Kavita is suffering from.$
Human Eye and Defects of Vision
Q3(5)(c) $Find the focal length of the lenses used in her spectacles.$
Lens Formula and Magnification

March 2016

5 q

Q2(3) $+2\,\mathrm{D}$
Power of a Lens
Q2(5) $A simple microscope is used by watch repairers. Give reason.$
Simple Microscope
Given below is a diagram showing a defect of the human eye. Study it and answer the following questions. (The figure shows parallel rays from an object being focused by the eye lens behind the retina.)
Q3(3)(i) $Name the defect shown in the figure.$
Human Eye and Defects of Vision
Q3(3)(ii) $Give reason for this defect of eye in human beings.$
Human Eye and Defects of Vision
Q3(3)(iii) $Name the type of lens used to correct the eye defect.$
Human Eye and Defects of Vision

The 10 board questions to practise first

The questions the board asked again come first, most asked first. Each one says how often and when.

Question 1
Asked 4 times: Mar 2022*, Mar 2023, Mar 2024, Jun 2026* (* = numbers or wording changed that year)
Q2(B)(ii) $एका बहिर्गोल भिंगाचे नाभीय अंतर 40 cm आहे, तर त्या भिंगाची शक्ती किती असेल ? The focal length of a convex lens is 40 cm. What is its power?$
Question 2
Asked 3 times: Mar 2018, Mar 2020*, Mar 2025* (* = numbers or wording changed that year)
Q4(i) $(a) मानवी डोळ्याची शास्त्रीयदृष्ट्या अचूक व नामनिर्देशित आकृती काढा. (b) निरोगी मानवी डोळ्यासाठी सुस्पष्ट दृष्टीचे लघुत्तम अंतर किती आहे ? (c) नाभीय अंतर आवश्यकतेनुसार बदल करण्याच्या नेत्रभिंगाच्या क्षमतेला काय म्हणतात ? (d) कोणत्या दृष्टिदोषांमध्ये वयानुरूप भिंगाची नाभीय अंतर बदलण्याची क्षमता कमी होते ? (a) Draw a neat labelled diagram of human eye. (b) What is the minimum distance of distinct vision for a normal human eye? (c) Name the capacity of the eye lens to change its focal length as per need. (d) Name the defect of eye vision in which the focussing power of eye lens decreases with age.$
Question 3
Asked 3 times: Mar 2016, Mar 2022, Jul 2024
Q2(A)(ii) $शास्त्रीय कारणे लिहा : घड्याळ दुरुस्तीमध्ये साधा सूक्ष्मदर्शी वापरतात. Give scientific reason: A simple microscope is used for watch repairs.$
Question 4
Asked 2 times: Mar 2020, Mar 2026* (* = numbers or wording changed that year)
Q1(A)(v) $निरोगी मानवी डोळ्याचे सुस्पष्ट दृष्टीचे लघुत्तम अंतर ____ आहे. For normal human eye, the minimum distance of distinct vision is ______.$
Tap an option to check your answer.
Question 5 (case study, 3 parts)
Asked 2 times: Mar 2018, Mar 2019* (* = numbers or wording changed that year)
Surabhi from Std. X uses spectacles. The power of the lenses in her spectacles is 0.5 D. Answer the following questions from the given information.
Q3(5)(i) $Identify the type of lenses used in her spectacles.$
Q3(5)(ii) $Identify the defect of vision Surabhi is suffering from.$
Q3(5)(iii) $Find the focal length of the lenses used in her spectacles.$
Question 6
This type asked 6 times: Mar 2016, Mar 2023, Mar 2024, Jul 2024, Jul 2025, Jun 2026. This one: Jun 2026
Q4(ii) $खालील आकृतीचे निरीक्षण करून विचारलेल्या प्रश्नांची उत्तरे लिहा : (अ) वरील आकृतीत दर्शवलेल्या दृष्टिदोषाचे नाव लिहा. (ब) या दृष्टिदोषाची कारणे लिहा. (क) या दोषाचे निराकरण कसे केले जाते ? (ड) या दृष्टिदोषाचे निराकरण करणारी आकृती काढा. Observe the following figure and answer the questions given below: (a) Name the defect of vision represented in the above figure. (b) State the reasons for this defect. (c) How is it corrected? (d) Draw the diagram to show the correction of this defect.$
Question 7
This type asked 4 times: Mar 2016, Mar 2018, Mar 2023, Mar 2026. This one: Mar 2026
Q4(i) $25$

Question 8

This type asked 3 times: Mar 2024, Jul 2024, Mar 2025. This one: Mar 2025

Q1(B)(iv)

योग्य जोडी जुळवा : ‘अ’ स्तंभ ‘ब’ स्तंभ साधा सूक्ष्मदर्शक (a) अतिसूक्ष्म वस्तूंचे निरीक्षण करणे (b) दूरच्या वस्तूंचे निरीक्षण करणे (c) घड्याळ दुरुस्ती करणे Match the columns: Column 'A' Column 'B' Simple microscope (a) used to observe minute objects (b) used to see distant objects (c) used for watch repair

Question 9
This type asked 2 times: Mar 2020, Jul 2025. This one: Jul 2025
Q2(A)(ii) $शास्त्रीय कारणे लिहा : डोळ्यापासून 25 cm पेक्षा कमी अंतरावर ठेवलेली वस्तू निरोगी डोळा स्पष्टपणे पाहू शकत नाही. Give scientific reason: We cannot clearly see an object kept at a distance less than 25 cm from the eye.$
Question 10
This type asked 2 times: Mar 2019, Mar 2022. This one: Mar 2022
Q3(vi) $2F_1$

Exercise

What the board has asked from this chapter

June 2026

March 2026

July 2025

March 2025

July 2024

March 2024

March 2023

March 2022

March 2020

March 2019

March 2018

March 2016

The 10 board questions to practise first

Question 1

Question 2

Question 3

Question 4

Question 5 (case study, 3 parts)

Question 6

Question 7

Question 8

Question 9

Question 10